Towing hitch for trailers



May 7, 1946. F; R. KLAUS ETAL 2,399,746

TOWING HITCH FOR TRAILERS Fil ed Apfil 15, 1945 4 Sheets-Sheet; 1

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Fiyl E INVENTORS F1 7' 4- Fred R. Klaus 'Fred M. Klaus BY W 7- ATTORNEYS I 4 Sheets-Sheet 2 F. R. KLAUS ETAL TOWING HITCH FOR TRAILERS Filed April 15, 1943 -/8 49 Z0 Z7 Z5 .ig- 7 59 48 INVENTORS Fred R. Klaus Fred M- Klaus BY fimw -r 71x4 ATTORNEYS May 7, 1946.

May 7, 1946.

F. R. KLAUS ET AL TOWING HITCH FOR TRAILERS Filed April 15, 1943 4 Sheets-Sheet 3 INVENTORS Fred R. Klaus ATTORNEY Fred M. Klaus BY gt/M4 r m May 7, 1946. F. R. KLAUS ET AL TOWING HITCH FOR TRAILERS 1945' 4 Sheets-Sheet 4 Filed April is ATTORNEYS Patented May 7, 1946 "UNITED STATES PATENT OFFICE 'rowmc. m'rcn FOR 'mamnns. Fred R. Klaus and Fred M. Klaus," Cleveland l lelghts, Ohio Application April 15,1943, Serial No. 483,086

6 Claims. (01. 188-142 Thi invention relates to a towing hitch for trailers and particularly to a towing vehicle and trailer combination including trailer towing and controlling devices interposed between the trailer and the towing vehicle.

An important object of the present invention is to provide an eflective automatic control of the trailer by means of suitablebrakes, an operating mechanism adapted to be actuated by forward pressure exerted by the trailer against the towing vehicle, the mechanism being also provided with means by which it can be operated manually.

A further object of the invention is to provide a brake operating mechanism which is adapted to be actuated automatically to set the trailer brakes when forward pressure is exerted by the trailer on the towing vehicle but which are operative only when the forward pressure of the trailer exceeds a predetermined amount.

A further object of the invention is to provide means for so regulating the pressure actuated controlling device as to vary'the'amount of presinvention may be said to comprise the towin hitch as illustrated in the accompanying drawings hereinafter described-aand particularly set 1 forth in the appended claims together with such sure which must be applied in order to actuate the brakes.

A further object of the invention is to provide a device which isadapted to be moved manu-' ally-to either of two positions to set the trailer brakes or to lock out the automatic brake actuating means.

A further object of the invention is to provide a device which is actuated upon an abnormal separation of the trailer from the towing vehicle variations and modifications thereof as will be apparent to one skilled in the art to which the invention pertains.

Figure 1 is a side elevation of a trailer and a towing hitch embodying the invention;

Fig. 2 is a top plan view of the trailer chassis and the towing hitch; a

Fig. 3 is a fragmentary view showing a portion of the drawbar with the cushioning spring mounted thereon.

Fig. 4 is a rear elevation of the jack caster viewed as indicated at 4-4 in Fig. l;

Fig. 5 is a top plan view on an enlarged scale showing the forward end of the trailer frame together with the coupling members and the brake actuating elements carried thereby;

Fig. 6 is a section taken on the line indicated at 6-6 in Fig. 5;

Fi '7 is a side elevation of the frame, coupling members and brake actuating devices shown in Fig. 5, a portion of the frame being broken away to show the drawbar and cushioning spring;

Fig. 8 is a fragmentary side elevation howing to automatically setthe trailer-brakes so that when the coupling beween the trailer and the towing vehicle is broken the trailer will be stopped.

Another object of the invention is to provide an automatic trailer brake operating device that includes a control spring which is so connected to the coupling elements that it serves as a shock absorber to cushion jerks exerted on the trailer as well as forward surges of the trailer.

A further object of the invention is to provide a suitable jack for supporting the'forward end of the trailer when it is uncoupled from the towing vehicle, the jack .being so designed that it may be easily and quickly moved to an extended or retracted position.

A further object is to provide an improved releasable coupling by which a universal connection is made between the trailer drawbar and thetowposition;

Fig. 9 is a section taken on the line indicated at 9-9 in Fig. 7 t

Fig. 10 is a sectional view showing a trailer wheel and the brake carried thereby, the section being taken on the line indicated at Iii-Ill in Fig.

Fig. 11 is a section taken on at ll-ll inFig. 10; a

Fig. 12 is a side elevation of a modified form of coupling;

Fi 13 'is a section taken onthe line I3--l3 in the line indicated Fig. 14 is a side elevation other position of adjustment; and v Fig. 15 is a top plan view of the coupling in the position shown in Fig. 14.

The accompanying drawings show a fragmentary portion of the rear end of a towing vehicle, a trailer chassis and the towing and controlling connections interposed between the towing vehicle and the trailer. As shown in Figs. 1 and 2, the trailer chassis comprises supporting. wheels I mounted on an axle 2 which support side frame members 3 which have converging forward end portions 4 which terminate in end portions 5 which are secured together face to face. Frame of the coupling in anmembers 4 are shown in the form of flanged bars which are secured together with their flanges disposed edge to edge to provide a recessed end portion to receive a coupling member.- A drawbar 6 is adapted to be detachably connected to a suitable connecting member such as a ball pivot l rigidly secured to the rear end. member I of the towing vehicle frame. The drawbar 3 has a yoke 9 at its forward end which is provided with aslot of suflicient size to permit the yoke to be slipped over the ball pivot I. The yoke 9 has a forward integral cross member III which has an inner bearing surface of substantially spherical curvature to fit upon the forward side of the ball pivot I.

Within the slot of the yoke there is pivotally mounted a rear bearing member II which has a spherical curved face adapted to engage the rear side of the ball pivot I to clamp the drawbar to the pivot and to complete a universal connection between the drawbar and towing vehicle. The bearing member II is connected to the yoke 8 by means of a horizontal transverse pivot l2 and has a rearwardly projecting arm |3 which extends horizontally within the slot of the yoke 9 when the bearing member is in pivot engaging position. For locking the member II in pivot engaging position a pivot II mounted on the yoke 9 and extending across the slot thereof carries a latch l adapted to engage the arm l3 of the bearing member to hold the same in pivot engaging position.

The'latch l5 has an actuating arm l6 by means of which the latch may be swung from a locking to a releasing position. The latch 5 is so formed that when the arm I6 is in its lowermost position engaging the top of the member H, the tip of the latch member l5 engages the arm I3 directly beneath the pivot I4 or slightly to the rear of the vertical Plane of the pivot axis so that thrusts exerted by the pivot I on the bearing member II will not'tend to disengage th latch. A transverse aperture lBa in the arm It may be registered withapertures in the portion of the yoke 9 to which the latch is pivoted to receive a padlock to prevent uncoupling of the towing vehicle from the trailer.

It will be readily seen that the bearing mem-' drawbar may be quickly and easily coupled to or uncoupled from the towing vehicle.

The drawbar 6 has a cylindrical portion II which slidably fits in a bearing member l8 which is mounted in the recess between the front end portions 5 of the trailer side frame members and rigidly attached to the end portions 5. The bearing member I8 has a rectangular slot l9 intermediate its ends through which the drawbar extends, and a coil spring 29 is mounted upon a. reduced portion IIa of the drawbar which extends through the slot I9. The spring 20 is mounted between front and rear seating disks or washers 2| and 2 2 which are slidably mounted on the drawbar, the forward movement of the front washer 2| on the drawbar being limited by the shoulder on the drawbar at the forward end of the reduced portion IIa. At its rear end the drawbar has a threaded portion 23 and a tip 24 of reduced diameter. An internally threaded cap 25 is screwed on the threaded portion 22 and shims 26 may be positioned between the bottom adjusted axially of the drawbar to apply a predetermined amount of initial pressure to the spring 20. The disks 2| and 22 provide adjustable sprlng seats on the drawbar which project beyond the periphery of the drawbar and of the cap 25. The spring seating disks 2| and 22 have a sliding fit in the slot l9 which is slightly wider than the bore which receives the portion I! of the drawbar and the cap 25. The ends of the slot |9 at opposite sides of the drawbar receiving bore provide ledges or abutments which engage with the spring seating disk 2| and 22.

When pull is exerted on the drawbar 8' a forward thrust is exerted on the spring 20 through the rear seating disk 22, and if this thrust is sufficient to compress the spring 29, the drawbar slides forwardly through the seating disk 2| which is held against movement with the drawbar by the shoulders of the member l8. When the trailer pushes forwardly a forward thrust is exerted upon the seating disk 22, and when the thrust is sufficient to compress the spring 20, the disk 22 slides forwardly on the drawbar.

In assembling the drawbar 6 with the member l8, the spring 20 and disks 2| and 22 may be posttioned in the slot IS, the drawbar may then be inserted endwise throug the Spring and is after which the cap 25 may be screwed on to the inner end of the drawbar to prestress the spring 29. v

The spring 20 provides a buffer for cushioning forward jerks by the towing vehicle for cushioning rearward bumps exerted by the towing vohicle in backing up and for cushioning forward thrusts exerted by the trailer in traveling downhill or when the velocity of the towing vehicle is sharply curbed.

The prestressing of the spring 29 by means of vehicle is started suddenly forward or back or in traveling up or down steep grades.

The bearing member 8 is slotted at its rear end to provide a pair of laterally spaced parallel arms 28 which provide a support for an actuating lever 29 mounted between the arms 28 on a horizontal pivot 30. The lever'29 has a forwardly projecting arm 3| which is normally positioned in the path of the rear end of the drawbar 6 so that the lever 29 is moved about its pivot upon rearward movement of the drawbar with respect to the trailer chassis. The lever 29 has a hook 32 at its lower end which engages in an eye 33 formed in an equalizer bar 34 midway between the ends thereof. Cables 35 are attached to opposite ends of the equalizer bar 34 and extend over guide rollers 36 carried by the side frame members 3 and the converging end portions 4 of the frame members. The cables 35 are atof the cap 25 and the end of the drawbar tip 24. 76 tached at their rear ends to brake actuating 1e.-

spear wardly to set the trailer brakes. Each cable 35 preferably has yielding connection to the equalizer bar 34 through 'a spring 35a to normally maintain a slight tension on the cables so as to insure immediate application of the trailer brakes when the spring is compressed by the forward thrust of the trailer. Individual adjustment of the tension of the springs a is obtained by adjusting nuts 35b against which the springs abut.

The lever 29 has a rearward extension 99 above the pivot 30 with which a cam 39 attached to a cross shaft 40 journaled in the arms 28 is adapted toengage. A lever arm 4| is attached to the shaft 40 and by means of the lever arm 4|, the shaft 4|) and the cam 39 may be turned manually in a clockwise direction, to the position shown in Fig. 8, to depress the extension 38 of the lever 29 and swing the hook 32 forwardly to set the trailer brakes. When the lever 4| is in vertical position, as shown in Fig. 7, the projection 39 is permitted to occupy its forward position and the lever 29 is held in brake releasing position by the cables 35 which are normally under the tension of the springs or other devices which normally hold the brake shoes out of contact with the brake drums. By means of the lever arm 4|, the trailer brakes may be set manually for parking or when the trailer is disconnected from the towing vehicle. A crank arm 42 is attached to one end of the shaft 49 and this crank arm is connected to a rod 43 which is mounted to slide longitudinally in a guide member fixed to one side face of the bearing member It. The forward end of the rod 43 is connected to the towing vehicle bymeans of a suitable cable such as a. chain 45 which is normally slack, but which is tautened upon an abnormally separating movement of the trailer with respect to the towing vehicle; thus if the coupling members should break apart, a

arm 4| in the position shown in dotted lines in 1'18. 7. i

when the trailer is a two wheel trailer, it is desirable toprovide means for supporting the forward end of the trailer frame when the trailer is disconnected from the towing vehicle. As herein shown, a supporting jack is provided which comprises a standard in the form of an upright rack bar 49 which is slidably mounted in the hearing member I! and which is operated by means of a pinion on a shaft 5| journalled in the bearing member it. The shaftil may be provided with a crank arm 52 by means of which the pinion may be turned to raise or lower the standard 49. The lower end of the standard 49 has a laterally projecting foot piece 53 which receives the pintle 54 of a fork 55 in which is journalled a caster wheel 56. The face of the standard 49 opposite that carrying the rack teeth is provided with spaced stop teeth 51 which slide in one direction past a yielding detent or latch 55 which is of cylindrical form and rotatably and slidably mounted in the forward portion of the member ii. The latch member 58 has a bevelled rear end face 59 and is pressed toward the standard 49 by means of a coil spring 50. The latch 58 has a thumb piece 6| at its forward end by means of which it may be turned to reverse the position of the bevelled'end 59. When the bevelled end 59 is in the position shown in Fig. 6, the standard 49 is free to move downwardly, but is prevented from moving upwardly by the latch 59. when the latch 58 is turned through 180 to reverse the position of the bevelled end face 59 as indicated in dotted lines in Fig. 6, the standard 49 can be moved upwardly by means of the pinion 59 but is locked against downward movement. With the latch .59 in the position. shown in' full lines in Fig. 6, the rack bar may be lowered to engage the wheel 55 with the ground and the v weight of the forward end of the trailer frame strong forward pull would be exerted on the rod v43 through the chain 45 which would tightly set the trailer brakes before the chain 45 is ruptured.

The lever 4| has a forward projection 41 adjacent its lower endwhich is provided with a notch it to receive the rear end of the cap 25 of the drawbar and to provide a stop for the drawbar which will prevent rearward movement of the drawbar in the member l8 sufficient to actuate the brakes through the lever 29. It will be seen that the drawbar locking portion of the lever 4| provides a means for locking out the pressure controlled brake actuating device so that the towing vehicle may be backed up and impart rearward movement to the trailer without causing operation of the trailer brakes.

It is desirable to prevent accidental displacement of the lever 4| from its brake setting and drawbar locking positions and this may be accomplished by providing the cam 39 with two recesses 39a and 391: which are adapted to be engaged alternately by a ball detent 390 which is positioned directly above the shaft 40, the engagement of the ball detent 390 with the recess 39a holding the lever arm 4| in the positionshown in Fig. 8 and engagement of the ball detent with the recess 99b serving to releasably hold the lever is imposed upon the standard 49 through the latch 59. To retract the standard 49 the position of the latch 58 is reversed so that the standard may be lifted freely and retained in elevated position by the latch.

In lowering the caster wheel 55 to supporting position, the standard 49 may be quickly ad- Justed by positioning the latch 58 to allow downward movement and stepping on the foot piece 53 and exerting a downward thrust thereon to rapidly move the rack bar and wheel downwardly until the wheel engages the ground. When the trailer is again coupled to the towing vehicle. the position of the latch 58 is reversed and the stzandard 49 is raised by means of the hand crank 5 As best shown in Figs. 2 and 10, the trailer axle 2 is provided with flanges 52 adjacent the ends thereof to each of which is rigidly attached a disk 89 which is positioned within a brake drum 54 mounted on a trailer wheel I. The brakes of the two wheels-are identical and each disk 63 has rigidly attached thereto a pin 55 which is positioned rearwardly of the axle 2 and upon which inwardly curved rear ends 65 of a pair of internal brake shoes 51 are pivoted, the rear ends 58 of the brake shoes being retained on the pivot pin 55 by means of a washer 68 held in place by means of an axially disposed screw 69. The forward end portions of the brake shoes 51 are connected forwardly of the axle 2 by a vertically disposed coil spring 10 which has its ends attached to inwardly projecting lugs 1| on the shoes 91. Between the forward ends of the brake shoes 61, the disk 63 is provided with a bearing portion 12 in which is journalled a shaft 13 which has oppositely projecting arms H connected by short links 15 to intumed forward ends 16 of the brake shoes 61. Turning of the shaft 13 in a counterclockwise direction, as viewed in Fig. 11, causes the toggle links H and 15 to force the ends of the shoes 61 apart and move the shoes 61 into engagement with the interior of the drum 84.

The actuating arm 31 is attached to the inner end of the shaft 13 so that a forward pull on the cable 35 moves the brake shoes into drum engaging position. The springs 18 connecting the brake shoes, serve to keep the cables taut so as to normally hold the lever 29 with its projection 38 pressing forwardly against the cam 39, as

shown in Fig. '7. The movement which can be imparted to the lever 29 either by the pressure of the draw bar on the projection 3|, or by the pressure of the cam 39 on the projection 38, is suillcient to move the shoes 61 to drum engaging position, and to apply effective pressure to the shoes of the lever 29 having sufllcient movement in excess of that initially required to set the brakes to compensate for wear on the brake shoes 61. Since the actuating arms 31 are attached to fixed operating shafts, the springs 16 of the brakes will maintain a substantially equal tension on the two cables. 35 to hold the lever 29 at the limit of movement shown in Fig. 7 and to insure release of both brakes upon release of the lever 29.

In Figs. 12 to 15 of the drawings, a modified form of draw bar coupling is shown. In this modification, a draw bar 88 is provided with a slotted end yoke 8| which has an integral front end bearing member 82 engageable with the forward side of a ball pivot 83. Within the slotted yoke, rearwardly of the bearing portion 82, a releasable bearing member 84 is provided which is mounted on a horizontal pivot 85 to swing toward or away from the rear side of the ball pivot 83 attached to a towing vehicle. An integral arm 86 extends upwardly from the bearing member 84 and this arm has an aperture 81 which'is adapted to register with apertures 88 in the yoke 8| and receive .a locking pin 89 to hold the bearing member 84 in engagement with the ball pivot 83. A second aperture 90 in the arm 86 is adapted to register with the apertures 88 when the bearing member 84 is swung to releasing position and the bearing member may be locked in a releasing position by the pin 89 passing through the apertures 90 and 88. The arm 86 is angle shaped so that its upper end is disposed in horizontal position when the bearing member 84 is swung to its rearmost position and the arm 86 has an eye 9| at its forward end which is adapted to receive an upwardly facing hook 92 attached to a towing vehicle. A suitable keeper bar 93 being provided to close the hook opening, the bar is held in place by means of retaining pins 94 and 96. The bearing members 83 and 84 may be employed to attach the drawbar to a pivotpin attached to an automobile bumper and the arm 86 and eye 9| may be utilized to attach to a connecting member mounted at a higher elevation on a towing vehicle such as a truck.

The principles of the present invention may be utilized in various ways, numerous modifications and alterations being contemplated, substitution of parts and changes in construction being resorted to as desired, it being understood that the embodiments shown in the drawings and described above are given merely for purposes of explanation and illustration without intending to limit the scope of the claims to the specific details disclosed.

What we claim is:

1. In a towing vehicle trailer combination, a drawbar adapted to be coupled to the towing vehicle, a member telescopically receiving the drawbar and connected to the trailer, said member having front and rear abutments adjacent the surface of the drawbar, a spring on the drawbar interposed between said abutments, a lever pivoted to said member and having a portion in the path of the rear end of said drawbar, a trailer brake, brake applying means operated by said lever, a manually operable lever mounted on said member, means controlled by the manually operated lever upon its movement in. one direction from a neutral position for actuating the first mentioned lever to apply the brake, and means controlled by the manually operable lever in the opposite direction from its neutral position for locking said drawbar against rearward movement in said member.

2. In a towing vehicle trailer combination, a drawbar adapted to be coupled to the towing vehicle, a member telescopically receiving the drawbar and connected to the trailer, said member having front and rear abutments adjacent the surface of the drawbar, a spring on the drawbar interposed between said abutments, a lever pivoted to said member and having a portion in the path of the rear end of said drawbar, a trailer brake, brake applying means operated by said lever, a manually operable lever mounted on said member, said lever having a cam portion engageable with the first lever to move the same to brake applying position, and an oppositely disposed latch portion engageable with the rear 4.0 end of said drawbar to restrain movement thereof toward the brake applying lever.

3. In a towing vehicle trailer combination, a drawbar adapted to be coupled to the towing vehicle, a member telescopically receiving the drawbar and connected to the trailer, said member having front and rear abutments adjacent the surface of the drawbar, a spring on the drawbar interposed between said abutments, a lever pivoted to said member and having a portion in the path of the rear end of said drawbar, a trailer brake, brake applying means operated by said 1ever, a second lever pivoted to said member, a cam operatively connected to the second lever and engageable with the first to move the same to apply the brake, and a cable connecting the second lever to the towing vehicle to actuate the same to apply the brake upon failure of the drawbar connection to the towing vehicle.

4. In a towing vehicle trailer combination, a draw-bar adapted to be coupled to the towing vehicle, a member telescopically receiving the drawbar and connected to the trailer, means for cushioning movements of said member with re spect to the drawbar, a trailer brake means actuated by said drawbar upon forward movement of the member. on the drawbar to apply said trailer brake, a manually operable lever, means controlled by the manually operable lever upon movement in one direction to set the brake, and means operable upon movement of the manually operable lever in the opposite direction to lock the drawbar against rearward movement in said member.

5. In a towing "ehicle trailer combination, a drawbar adapted to be coupled to the towing vehicle, a member telescopically receiving the drawbar and connected to the trailer, means for cushioning movements 01' said member with respect to the drawbar, a lever pivoted to said member and having a portion disposed in the path of movement or a portion of said drawbar. trailer brake operating means operated by said lever, and a second manually operable lever having a portion engageable with the flrstmentioned lever upon movement of said second lever in one direction to move the first lever to brake applying position, and a. portion which upon movement in the opposite direction blocks the rearward movement of the drawbar.

6. In a towing vehicle trailer combination, a drawbar adapted to be coupled to the towing vehicle, a member telescopically receiving the drawbar and connected to the trailer, means for cushioning movements of said member with respect to the drawbar, a lever pivoted to said member and having a portion disposed in the path or movement of a portion of said drawbar. trailer brake operating means operated by said lever, a manually operable lever having a cam engageable with said brake applying lever and movable to a position in which said brake applying lever is locked in brake applying position bysaid cam, and a cable connecting said manually operable lever to the towing vehicle to move the same to brake setting position upon failure of the drawbar connection to the towing vehicle.

' mm B. mus. man M. mus 

